AI agents call get_file_coverage to retrieve information from Simplecov without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only queries and retrieves existing SimpleCov coverage metrics from Ruby test reports. It performs no creation, modification, deletion, or execution of code. The tool is part of a coverage analysis suite (alongside list_files, get_summary, get_uncovered_lines) all designed for inspection and filtering of test coverage data. No side effects or state changes result from using this tool.
From the tool's definition Tool retrieves coverage report data without modifying or deleting anything. Description indicates it 'gets detailed coverage information' including 'hit counts per line, uncovered lines, and branch coverage' - all read-only data retrieval operations.
Attacks that exploit this kind of access
特定ファイルの詳細なカバレッジ情報を取得する。行ごとのヒット数、未カバー行、ブランチカバレッジを含む。. It is categorised as a Read tool in the Simplecov MCP Server, which means it retrieves data without modifying state.
Register the Simplecov MCP server in PolicyLayer and add a rule for get_file_coverage: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Simplecov. Nothing to install.
get_file_coverage is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_file_coverage rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for get_file_coverage. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
get_file_coverage is provided by the Simplecov MCP server (ryo-ymd/simplecov-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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